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Search: id:A145540
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| A145540 |
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a(n)=number of numbers removed in each step of Eratosthenes' sieve for 10^4 |
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+0
19
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| 4999, 1666, 666, 380, 207, 159, 110, 94, 76, 59, 56, 46, 41, 37, 33, 27, 23, 21, 17, 15, 12, 9, 8, 6, 3
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Number of steps in Eratosthenes' sieve for 10^n is A122121(n).
Number of primes less than 10^4 is equal = 10^4 - (sum all of numbers in this sequence) - 1 = A006880(4).
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MATHEMATICA
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f3[k_Integer?Positive, i_Integer?Positive] := Module[{f, m, r, p}, p = Transpose[{r = Range[2, i], Prime[r]}]; f[x_] := Catch[Fold[If[Mod[x, #2[[2]]] == 0, Throw[m[ #2[[1]]] = m[ #2[[1]]] + 1], #1] &, If[Mod[x, 2] == 0, Throw[m[1] = m[1] + 1]], p]]; Table[m[n] = -1, {n, i}]; f /@ Range[k]; Table[m[n], {n, i}]]; nn = 4; kk = PrimePi[Sqrt[10^nn]]; t3 = f3[10^nn, kk] (*Bob Hanlon*)
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CROSSREFS
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A006880, A122121, A145532-A145540
Sequence in context: A116147 A108837 A070001 this_sequence A031840 A059667 A106767
Adjacent sequences: A145537 A145538 A145539 this_sequence A145541 A145542 A145543
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KEYWORD
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fini,nonn
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AUTHOR
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Artur Jasinski with assistence from Bob Hanlon (grafix(AT)csl.pl), Oct 14 2008
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